<!DOCTYPE html>
<html>
<head lang="en">
    <meta charset="UTF-8">
    <title>link</title>
    <style>
        body{
           width: 100%;
        }
        a{ width: 200px;height: 200px;margin:0 auto; }
        a:link {color: #FFF} /* 未访问的链接 */
        /*a:visited {color: #00FF00} /!* 已访问的链接 *!/*/
        /*a:hover {color: #FF00FF} /!* 当有鼠标悬停在链接上 *!/*/
        /*a:active {color: #0000FF} /!* 被选择的链接 *!/*/
    </style>
</head>
<body>
<a href="#">link</a>
</body>
</html>